The present invention relates to a program, an information storage medium, an image generation system, and an image generation method.
An image generation system (game system) has been known which generates an image viewed from a virtual camera (given viewpoint) in an object space (virtual three-dimensional space) in which an object such as a character is disposed. Such an image generation system is very popular as a system which allows the experience of so-called virtual reality.
In such an image generation system, it is desirable to realistically represent a mark formed on the ground by an object having a complicated unevenness, such as a tire or a shoe sole, in order to increase the virtual reality of the player.
In related-art technology, when representing tire tread marks on the ground, the tire tread marks are represented by texture mapping a mark image or representing shade (shading) based on a normal vector, for example. However, such related-art technology cannot provide a three-dimensional impression due to insufficient representation of tire tread unevenness.